This looks a LOT like what I'm experiencing for the past month (a year after James) on my N800. I can't update or install anything while on a boot from SD session. When I boot from flash, no problems at all. The background is simple -- I haven't done anything to the N800 to point to. One day it worked fine, the next day I can't update (and no recent Automatic Update alerts either).

So I'm sure I can reformat the SD and start from scratch, but it's a 16GB and I've got all my programs installed on it. I don't want to have to start from scratch.

Is there anything I can do? In this thread Qwerty and James talk about reformatting the internal memory card. If they mean the internal memory, cool... but if they mean the SD inside, I don't know what to do because I don't want to reformat.

Any ideas?